Work machines, such as motor graders, are used for geographic surface altering operations. Motor graders include a work implement, such as a surface altering blade or moldboard, that is movably connected to a main frame of the motor grader. Typically, the motor grader blade is suspended from the main frame by means of a drawbar and circle support assembly. The assembly has a forward end connected to the front of the motor grader main frame by a ball and socket connection, while the rearward portion of the assembly is suspended from the main frame by hydraulic actuators which permit the assembly to swing in a vertical plane about its front end. The grader blade is mounted to a circle through blade supports, and the circle is mounted for rotation relative to the drawbar and circle support assembly about an upright axis to allow an operator to locate the grader blade in an appropriate angular position relative to the assembly for performing various work functions.
In the past, while the position of the grader blade was angularly adjustable about an upright axis through rotation of the circle, and further adjustable in a vertical plane through swinging movement of the drawbar and circle support assembly about its forward end, the fore and aft longitudinal position of the grader blade relative to the motor grader main frame was fixed.
However, those skilled in the art will appreciate that the longitudinal position of the grader blade relative to the main frame is critical to the proper function of the blade in a grading operation over a relatively wide range of motor grader speeds. As motor grader speed is increased beyond a certain limit in a grading operation, it is possible that the forces acting on the grader blade may cause the work machine to bounce and the grader blade to scallop the road surface. Moreover, the fixed longitudinal position of the grader blade limits blade reach and positioning capabilities, as well as limiting the ability of the operator to align the blade with other machine implements that are mounted to the motor grader.
The present invention is directed to overcoming one or more of the problems as set forth above.